leasure



Aug. 18, 1959' w. c. LEASURE 2,899,

APPARATUS FOR PACKAGING Filed Dec. 28 1956 '4 Sheets-Sheet 1 W/ 0/77 C Aemu/re INVENTOR.

Filed Dec. 28, 1956 18, 1959 A w. c. LEASURE v 2,899,875

APPARATUS FOR PACKAGING 4 Sheets-Sheet, 2

IN VEN TOR.

W////am C. lean/re Aug. 18, 1959 w. c. LEASURE 2,399,875

APPARATUS FOR PACKAGING Filed. Dec. 28, 1956 4 Sheets-Sheet 3 W/ ///0/7?C Leann/re INVENTOR IVFBY Aug. 18, 1959 w. c. LEASURE V 2,399,875

' APPARATUS. FDR PACKAGING Filed Dec. 28, 1956 4 Sheets-Sheet 4 ,J I I II I I I I I ?i, W I .6 I I I I 7 I I I 6 5 1- II III I i I I 7654521 25567 l \J I I I INVENTOR MLA/AM c. LMSdkE,

BY jw w ATTORNEKS nited States Patent APPARATUS FOR PACKAGING William C.Leasure, Houston, Tex., assignor to Mira-Pair, Inc., Houston, Tex., acorporation of Texas Application December 28, 1956, Serial No. 631,342

7 Claims. (Cl. 93-82) The present invention relates to a method andapparatus of packaging and more particularly to a method and apparatusof forming packages or containers from strip packaging film by passingthe film over a specially constructed former.

Various devices are in use at the present time for forming containersfrom strip packaging film and charging or filling such containers withproduct. Such devices include a paper former which is adapted to receivethe strip packaging film and position it for passing it between avertically arranged inner former tube and outer former tube so as toform the strip packaging film into tubular or tubelike containers orpackages. Suitable means are provided for pulling the strip package filmlongitudinally of the vertically arranged inner and outer former tubesand for sealing the longitudinal edge portions of the strip packagingfilm. As the strip packaging material is pulled longitudinally betweenthe inner and outer former tubes, products are discharged through theinner former tube and into the tube-like container and the containersare thereafter sealed at both ends so as to enclose the product therein.Such packaging machines are, for example, disclosed in the patent toZwoyer, 1,986,422, issued January 1, 1935.

The operation of forming the container, sealing it 1ongitudinally,charging it with product, and sealing the tubelike container laterallyat spaced portions so as to form a closed container is carried outstep-Wise and automatically by the above devices. There are, however,certain objections to the above method and apparatus Since the packagesor containers are filled by passing the product or merchandise throughthe inner former tube, the sizes and quantity of the product ormerchandise that may be placed in a given container or package as it isbeing formed in presently known apparatus is limited by thecross-sectional area of the opening of the inner former tube and thespeed at which the product is being fed into the container, as well asthe speed at which the containers are being closed ofi. The opening sizeof the inner former tube also limits the size of the product ormerchandise that may be fed into a package or container, and since onlya certain volume of product or merchandise may be discharged through atube opening of a given size in each filling cycle, it seems obviousthat under some circumstanes the speed of operation of the automaticmachine of present day constructions must be adjusted accordingly, to aspeed to accommodate those situations where the filling of the bag as itis being formed required additional" packaging film as it passes betweenthe inner and outer Patented Aug. 18, 1959 former tubes to such anextent as to interfere with the automatic operation of forming, fillingand sealing.

Additional interruption of the automatic sequence of present daypackaging apparatus'is caused where the material or product being fedthrough the inner forming tube bridges the opening so as to stop it upeither completely or to such an extent as to interfere with the properfeeding or discharge of the product or merchandise from the inner formertube and into the tube-like container being formed.

The present invention is directed to a method and apparatus of packagingwhich overcomes all of the above and other objections encountered withpresent day autoformer in' such a way that it maintains the materialtaut and supports the material throughout the forming opera tion. Thespecific former disclosed herein which is for use in forming tubularcontainers has a tubular end portion with overlapping edges, anintermediate curved por tion forming wings on the tubular portion toshape the strip material in tubular form and a curved end portion toreceive the strip material. The shaping of the former is mathematicallycalculated so that a former for any type or size of container may bereadily designed. By eliminating the inner former of prior art packagingmachines all of the disadvantages inherent in such structures areovercome and certain advantages are achieved which were not possibleheretofore.

By eliminating the inner former the full volume of the container may beutilized for filling with product. Furthermore, the strip material mayconstitute a conveyor to convey the product into the package. As broughtout hereinbefore, the product frequently became jammed within the innerformer of prior art packaging machines and the obviation of thisdiificulty constitutes a major advance in the art.

An object of the present invention is to provide a method and apparatusof continuously forming containers or packages of strip packaging film,charging the containers with product, and sealing the container to forma closed bag wherein the inner former tube heretofore used is eliminatedwhereby the product or merchandise may be discharged directly into thecontainer or package as it is being formed.

Yet a further object of the present invention is to provide 'a methodand apparatus of automatic packaging wherein the strip packaging filmWhich'for-ms the container or package is utilized as a conveyor toconvey merchandise or product into the container as it is formed wherebyany productor merchandise may be automatically packaged without damageor injury thereto.

Yet a further object of the invention is to provide a method ofautomatic packaging wherein the product or merchandise being packagedmay be conveyed into the package as it is formed without damage orinjury to the merchandise or product.

Yet a further object of the invention is to provide a packaging methodand apparatus wherein a more efficient filling of a package may beobtained per unit volume of container, and in an amount of time lessthan heretofore possible with prior art devices.

Still another object of the present invention is to provide an apparatusfor forming packages or containers of strip packaging film wherein abetter longitudinal edge seal may be obtained on the tube-like structurethan heretofore possible with prior art devices.

Even a further object of the present invention is to pro-' r 3 v-ide anautomatic packaging method and apparatus for forming packages orcontainers of a continuous strip of packaging film wherein the packageand the filling thereof maybe accomplished in any desired plane'to suitthe type of merchandise without causing damage thereto.

Other objects and advantages of the present invention will become morereadily apparent from a consideration of the'following description anddrawings wherein:

Fig. 1 is a side elevation, partly in section, illustrating a form ofthe present invention;

Fig. 2 is a vertical sectional view on the line 22 of Fig. 1 showing thearrangement of the edge portion sealing means; 7

Fig. 3 is a view on the line 3-3 of Fig. 1. and is a front elevationalview of the form of the invention of Fig. 1 and illustratingschematically a form of automatic weighing and dumping means for themerchandise or product that is placed in the package;

Fig. 4 is a side'elevation illustrating an alternate modification of thesealing means for sealing the edge portions of the strip packaging filmmaterial; A Y

Fig. S is a sectional view along the line S5 'of Fig. 4;

Fig. 6 is a view showing still another modification of the sealing meansfor sealing the longitudinal edge portions of the strip packaging filmmaterial; and.

Fig. 7 is a view showing the method of designing a former.

Attention is directed to Fig. 3 of the drawings wherein thepresentinvention is illustrated asv being supported by suitable framework so asto position the various. components in proper relationship to accomplishthe desired aims and objects of the invention. As illustrated, theframework may consist of side members 3 and 4 which are suitably spacedso as to receive the rollers 5 and 6, and the drum or roll 7 of strippackaging film material.

As more clearly illustrated in Fig. 1 of the drawings, the strippackaging film is rolled off drum 7 and is guided over the roller 6 andunder the roller 5 to be received on the forming shoe 8. If desired, thespindle 5' and 6' of the rollers 5 and 6. respectively, may be receivedin any suitable means such as longitudinally extending slots or the like(not shown) in the side members 3 and 4 whereby the rollers 5 and 6 maybe adjusted vertically relative to each other to obtain the propertension in the strip packaging film 9 as it moves thereover. The formingshoe 8 may be positioned in the frame 2 by any suitable means such asthe brackets 11 and 12 respectively, which brackets are secured to theside members 3 and 4 so as to position the forming shoe 8 at a desiredelevation within the framework 2 to receive the strip packaging film 9from the roller or drum 5. 7

It will be noted that the forming shoe 8 serves to form the strippackaging film material into a tubular or tubelike form as illustratedat 14 whereby a containeris pro vided for receiving merchandise orproduct represented at 18 therein.

The design of this forming shoe so that it forms the strip film into acontainer shape without an inner mandrel is a critical feature of thisinvention and will be described in greater detail hereinafter. i

A baffle plate 16 may be provided on the top 15- of the frame 2 foraiding in discharge of merchandise or prod uct from the automaticweighing and dumpinglmechanism illustrated schematically in Fig. 3 andgenerally designated by the numeral 16. Particular attention is.directed to the fact that the product or merchandise 18 is dischargeddirectly into the open top 17 of the tube-like container 14 as it isbeing formed by the shoe 8.

In automatic packaging apparatus presently in use, the strippackagingfilm is passed over a paper former and guided'verticallybetween an inner former tube and an outer former tube wherebya tubularortube-like container or package is. formed. Die meansare provided forabutting the longitudinal edge portions of the strip packaging film onthe outside and against the innGI forming tube on the inside of thelongitudinal edge portions so as to seal such longitudinal edge portionsof the film 9. It can be appreciated that if excessive pressure isapplied by the sealing die against the inner forming tube of the priorart devices, there is a possibility of misaligning the inner formingtube relative to the outer forming tube to the extent of binding thestrip packaging film as it moves therebetween.

This may interfere with or even interrupt the automatic sequence offorming, filling and sealing the containers. The present inventionovercomes this problem by completely eliminating the inner formermandrel of the prior art constructions. As illustrated in the drawings,for example in Fig. 3, it will be noted that'the edges 20 and 21 of thestrip packaging film 9 overlap each other as the film is discharged fromthe forming shoe 8. It is generally customary to provide the edgeportions 20 and 21 of the strip packaging film with a heat sealingcompound so that such longitudinal edge portions-may be sealed in orderto form a tubular member or package 14.

Sealing means indicated generally by the numeral 28 are provided in thepresent invention for sealing along the longitudinal edge portions 20and 21 of the strip package film 9. The means 28 includes an arm 30which is secured at its upper end 31 to the top 15 of the frame 2, sucharm extending downwardly into the forming shoe 8 as illustrated in Figs.1 and 3 of the drawings. An arm 33 is pivotally secured at 34 to theside of the frame 2 and includes the U-shaped bracket 33- which slidablysupports the shoe 32. Spring means 32" may be mounted in any suitablemanner to yieldingly urge the shoe 32- against the edge portions 20- and21 and is shown as being mounted in the bracket 33 so as to abut therear of shoe 32 and yieldingly urge it toward the arm 30 so as to sealthe edge portions 20 and 21 as they move longitudinally between the shoe32 and the arm 30. Suitable electrical leads as illustrated at 35 areprovided for heating the shoe 32, the longitudinal edge portions 20. and21 and adjacent portion of arm 30 to aid informing a proper seal betweenthe longitudinal edge portions 20 and 21.

Fig. 4 illustrates an alternate arrangement of the sealing means 28wherein a bracket 36 is shown as being mounted on the top 15 of theframe 2. Such bracket pivotally supports the arm 30 on which is mountedthe shoe 29' at the lower end thereof and-inside of the tubular packageor container 14. 'IFhearm. 30'-is bent downwardly as illustrated at 30"and is secured at its lower end to the piston rod 38 in cylinder housing38. The cylinder housing 38 is slidably mounted on the pins 39 and 40which pins project from the depending frame portion 41. 7

A shoe 32' is secured to the inner end of the cylinder housingso'thatwhen fluid is supplied. through the port 43 of the housing 38relative longitudinal movement be tween the piston rod 38' andthehousing 38is effected,

' thereby moving the sh0es29 and 32. towards each other to effectsealing of the edge portions of the strip packaging materialtherebetween. A power lead 35 is shown whereby the sealing shoes areheated .to aid in sealingthe edge portions 20 and 21. v

The dies 29 and 32' may be moved awayfrom each other by discharge fluidthrough opening or port 43' so the reverse relative movement between thepiston rod 38 and housing 38 may occur, thereby separatingdies 29 and32. a

To aid in pulling the strip packaging material over and longitudinallyof the forming shoe 8 andto seal endportions 26 and 27 of the tubularcontainer 14 so as to form closed packages as illustrated at 51,suitable die means as illustrated at 25 are provided for engaging theformed tubular container'14 as shown in Figs. 1, 3 and 40f the drawingsso as to pullthe packaging film 9 over the shoe 8 to form it into thetubular member 14. The dies 25 seal off the lower end of the tubularcontainer or package 14 so that thereafter suitable means may cut thelower end of the tubular member 14 after it has been sealed.

The die 25 then reciprocates or moves upwardly and again grasps thetubular member 14 to pull it longitudinally of shoe 8 and seal it sothat it can thereafter be cut.

The construction, arrangement and operation of the shoe meansillustrated generally by the number. 25, as well as the cutting means iswell known in the art and is illustrated by any one of several patents,such as that illustrated by the patent to Zwoyer, No. 1,986,422, issuedJanuary 1, 1935. It is, therefore, believed unnecessary to give adetailed description of the dies 25 as they form no part of the presentinvention.

Also, it should be understood that the stepwise operation of the variouscomponents of the invention is synchronized so that the sealing of thelower end of the formed tubular portion 14, the filling thereof withmerchandise or product, as well as the longitudinal edge sealing and thecutting of the package into bags of suitable length is carried out in adesired manner. The means for synchronizing these functions are wellknown in the art and it is, therefore, believed unnecessary to give adetailed description thereof in the present application.

Referring now to Fig. 7 the manner in which a former is designed will bedescribed. Assuming a bag with a width of 4 is desired, draw a circlewith A as its center with radius of 4". Draw radial lines on both sidesof avertical radius 30 to each side. As pointed out hereinbefore, anyrelative line within the shaded areas could be used but normally theparticular pattern line ECPGA FOBD is desirable for most films,preventing paper fracture and wrinkling. Obviously, as soon as thepackaging film from the roll comes into contact with the former, theshaping process is begun. However, the line ECPGA FOBD may be considereda final line of transformation between the wing portion of the formerand. the tubular portion. This line has a length substantially equal topi times the radius AC. This is true due to the fact that the additionallength of GA F over GA F to provide crown is substantially the same asthe amount of reduced length in the arcs CPG and BOF over the other arcsbetween C'and G and B and F. Since the radius AC is equal to the widthof the bag or half the circumference, it follows that the length of theline of transformation is substantially equal to pi times onehalf thecircumference of the tubular portion. Let the radii intersect at pointsF and G. Draw radial lines below the horizontal diameter of the circleat an angle again of 30, calling the intersection of the radii M and N.Draw MG and NF, calling their intersection 0n the vertical axis A A A isthe diameter of completed tube portion of the former. Strike a circulararc FG with its center A letting this are intersect the vertical'radiusat A Draw arcs CG and BF with centers at M and N which flow smoothlyinto arc FA G, continue from B and C to edges of film width whichcompletes in this example a /2 back seal.

The area within ECPGA FOBD represents the pattern for the tubularportion of the former.

The area outlined by ECPGA FOBD and extending to an arbitrary length forconstruction needs in this example to H, becomes the pattern for thewings of the former.

The pattern line could follow any relative line within the shaded areabut it is found that pattern line ECPGA FOBD is desirable to preventpaper fracture and wrinkling.

With these patterns, the templates for the tube and wings are madeallowing for mean diameter and other factors, determined by metalthickness to be used, which are well known in the pattern makers art,allowing the finished former pitch line represented in this example. as

It is now readily seen that the primary consideration in designing thisformer is to insure that the packaging film when under tension anddeveloping into a tube-- like structure is bearing on all parts of theformer ex actly as if it were still in the flat. It has been found thata former of this design supports the packagingfilm completely withpressure on the film equalized over the entire wing area, with frictioneffective over the entire wing area, from the first contact point untilthe film is completely enveloped into a tube-like structure, holding thepackaging film firmly in tube-like form, thus removing the necessity foran inner mandrel such as used in prior art.

While this explanation covers that for designing a former for a 4" bag,it is obvious that similar procedures will be followed for other sizes.

As previously mentioned, in prior art devices an inner forming or formertube is provided which extends downwardly into the tubular package orcontainer 14 as it is being formed. Product or merchandise to bedischarged into the tubular container or package is passed through theinner forming mandrel and into the tubular container or package 14. Suchconstruction and arrangement has many disadvantages. For example, it isnot unusual for material as it passes through the inner former mandrelof the prior art devices to stop up the opening in the inner former tubeor to interfere with the passage of product therethrough to such anextent as'to improperly fill the tubular container 14, therebynecessitating interruption of the automatic packagingapparatus to clearout the opening in the inner former mandrel.

Additionally, the inner former mandrel of prior art constructionsgreatly restricts or interferes with passage of merchandise or productinto the tubular container. Generally, the inner former mandrel isone-quarter of an inch thick and, for example, when producing a fourinch wide bag, the cross-sectional area of the passage opening in theinner former tube is 3.29 inches, whereas the cross-sectional area ofthe opening into the tubular container 14 without the inner formermandrel is 5.11 inches, which means that the removal of the mandrelincreases the cross-sectional area of the opening into a container 14 ofa four inch bag in excess of fifty percent. It can be appreciated thatsince the present invention eliminates the inner former mandrel of theprior art constructions, the material or merchandise may be fed into thecontainer 14 more rapidly so that a more efit'cient filling of thecontainer 14 can be accomplished per unit volume of container, and in aminimum amount of time.

Additionally, allautomatic packaging machinery of prior artconstructions is constructed and arranged so that the merchandise orproduct is discharged by gravity downwardly and into the tubular packageor container 14 as it is being formed. The gravity feed of the productor merchandise is disadvantageous because certain products such astomatoes or other fruit or other merchandise may be damaged by thegravity feeding method, and also where the product is light, such as inthe case of potato chips, the filling of the tubular container 14 isrelatively slow. The present invention overcomes this objection in thatit provides an arrangement whereby the charging or filling of thetubular container 14 may be conducted horizontally, or at any suitableangle.be tween horizontally and vertically. Additionally, as the film 9passes over the shoe 8, it actsas a conveyor for engaging themerchandise or product to be discharged into the tubular package 14 soas to convey -it into the package. This permits. the present inventionto .be arranged horizontally met any desired angle between verticallyandhorizontally-so that merchandisewhich might otherwise be damaged bygravity feeding or mechanical feeding, such as used in presentconstructions maybe fed into packages formed by" the present method'andapparatus without being harmed.

It should be additionally noted thatsince the inner former mandrel ofprior art constructions is eliminated it is possible to fill a containerwith Iargerproducts, since heretofore the size product in the containerhas been restricted or limited to the diameter of the opening in theinner forming mandrel, Whereas, in the present invention the size of theproduct of merchandise may be substantially the same size as the bagbeing formed because the product is discharged directly into the bag. Ihave previously pointed out by way of example that on a four inch sizebag the present invention enables merchandise of at least fifty percentgreater size to be discharged into the bag and also a fiftypercentincrease in volume of product is permitted thereby greatly speeding upthe whole operation while attaining a more eifcient relationship of theproduct to the bag size being formed.

It can be readily appreciated, from the foregoing,.that under somecircumstances it may be desirable to position the present invention atsome angle between the horizontal and vertical and to adjust the rate ofmovement of the strip packaging film 9 in relation to the angle offeedto convey the product 18 intothe tubular package or container 14 at apredetermined or desired rate. In some situations, it may be desirabletoarrange the present invention so that the containers 14 are formed in ahorizontal plane, thereby permitting substances which might be damagedor injured by feeding mechanisms of the prior devices to be dischargedinto tubular containers 14 as they are being formed without damagethereto.

In some situations, it may be desirable to aid in maintaining thetubular form of the strip packaging material as it is being formed or asthe merchandise or product is being discharged thereinto. To accomplishthis function, suitable suction means as illustrated at 50in Fig. 4 maybe provided. It will be noted that the shoe 8 is provided with anextension and a plurality of open ings 51 in the lower end thereofcommunicate with the annulus 52 formed between the cover 52 and theextension of shoe 8. A pipe 53'communicates with the annulus 52 whichpipe may be engaged with suitable means for creating a suction or vacuumin thepipe 53, which reduced pressure tends to draw air into theopenings 51 of the shoe 8. This in turn draws the packaging film 9adjacent the openings 51 toward the openings as illustrated at 54 so asto hold the strip packaging film against the rear portion of the shoe 8away from the sealing shoe 29'. This construction may be provided incertain situations so as to help in holdingthe bag opening open as it isbeing filled with product or merchandise.

It seems readily obvious that the suction means of Fig. 4 may beeasilyapplied to the form of the invention illustrated in Fig. 1 by elongatingthe rear portion of the shoe 8 to provide a means for receiving thesuction mechanism as indicated generally by the numeral In othersituations it may be desirable that the shoes take the form of rollers29 and 32", respectively, as illustrated in Fig. 6 of the drawings. Hereagain, suitable electrical means may be provided as illustrated at 35for heating the rollers to seal the edge portions 20 and 21 of the strippackaging film 9.

The rollers may be mounted in fixed relationship as described withregard to shoes 29 and 32 in Fig. 1 and Fig. 3.modification, or they maybe-mounted for movement relative to each other 'as shown in Figs. 4, and5,.v

It should be readily obvious that any suitableframe for supporting thevarious components ofv the present invention may, be. utilized-'1 andthatdescribedherein is for-the purposes ofiillustration. only. Also, anysuit! able automatic weighing and dumping mechanism which is well knownin the art maybe utilized in cooperation with the present invention. 7 I

Aspreviously described, the power supply and means for automatically andstep-wise synchronizing the various steps of the present invention iswell known inthe prior art and attention is directed to the patent to W.R, Zwoyer, previously referredto herein, which illustrates one form ofsuitable synchronizing means which may be practiced with the presentinvention.

From the foregoing description itcanbe. seenthat the present inventionrelates to a packaging method and apparatus wherein the inner formingmandrel-of prior art devices is eliminated. This enables thevmerchandise or product .to be charged directly into the package as it isformed, thereby eliminating the problemsof prior art automatic packagingapparatus where the inner forming tube is utilized. The .presentinvention also provides a sealing arrangement for the longitudinal edgeportion of strip packaging material as it is being formed into tu bularpackages or containers wherein the sealing shoes are mounted oppositeeach other, one on theinside of the tubular formed packaging material 14and,the other on the outside so that the desired sealingof the edgeportions 20 and 21 may be accomplished without the possibility ofinterfering or interrupting the sequence of automatic packagingapparatus.

Broadly the present invention relates to amethod-and apparatus forautomatic packaging and.particularly to amethod and apparatus forforming a continuous strip of packaging film into a container,chargingthe container with product or merchandise and sealing; ittoenclose the merchandise or product therein. Whilethe container shapedisclosed herein is circular, it is readily apparent that the former maybe adapted to any shape of container according to the method hereindescribed.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a packaging machine of the class described, a former fortransforming sheet material into tubular form, said former havinga backportion, curved wingportions and a tubular portion, said back portionextending at an acute angle with respect to said tubular portion, a lineof transformation between said curved wing portions and said tubularportion, the line of transformationhaving a length substantially equalto one-half the circumference of said tubular portion times pi.

2. In a packaging machine, a sailor collar shaped external former forshaping sheet material into tubular form, said former including atubular neck and wing portions, the tubular neck of said former havingthe front portion thereof displaced a substantial distance from the rearportion thereof along the longitudinal axis of the tubular neck, thewing portions of said former extending from said front portion to saidrear portion, the

wing portions being integral with a back portion, the

back portion extending at an acute angle with respect to said tubularneck.

3. In a packaging machine, a former for transforming sheet material intotubular form, said former comprising a back portion, curved wingportions and a tubular portion, the wing portion being integral with theback portion, the back portion extending at an acute angle with respectto said tubular portion, saidformer developable from an integral fiatsheet of material, the area of said integral fiat sheet of materialbeing equal to the area of said back, wing and tubular portions.

4. A former according to claim 3-wherein a'line of transformationextends between the tubular portion and the-wingand back portions, saidlinehaving. a, length equal to one-half the circumference of the tubularportion times pi.

5. In a packaging machine in which sheet material is transformed into atubular shape by passing over a former, the former having a tubularsection, wing sections and a back section, a line of transformationextending between the wing sections and the tubular section, said linehaving a length equal to one-half the circumference of the tubularportion times pi, and means for sealing the longitudinal edges of thematerial together when in tubular form, said means including an elementextending into the tubular section of said former.

6. In a packaging machine, a former for transforming sheet material intotubular form by passing over a former, said former comprising a backportion, curved wing portions and a tubular portion, the wing portionsbeing integral with the back portion, the back portion extending at anacute angle with respect to said tubular portion, said formerdevelopable from an integral fiat sheet of material, the area of saidintegral fiat sheet of material being equal to the area of said back,Wing and tubular portions, a line of transformation between the wing andtubular portions, said line of transformation having a length equal toone-half the circumference of said tubular portion times pi, said formersupporting the sheet material equally in every area increment on theWing and back portions throughout the transformation of the materialfrom sheet to tubular form.

7. In a packaging machine, a former for transforming sheet material intotubular form, said former comprising integral wing and back portions, aline of transformation forming the forward edge of said wing and backportions, said line of transformation having a length substantiallyequal to one-half the circumference of the tubular formed sheet materialtimes pi, the back portion extending at an acute angle with respect tothe tubular formed sheet material.

References Cited in the file of this patent UNITED STATES lATENTS987,440 Dichmann Mar. 21, 1911 2,099,257 Bergstein Nov. 16, 19372,113,078 Campbell Apr. 5, 1938 2,162,230 Salfisberg June 13, 19392,200,971 Sonneborn et a1. May 14, 1940 2,248,471 Stroop July 8, 19412,257,433 Stokes Sept. 30, 1041 2,331,762 Brown Oct. 12, 1943 2,387,812Sonneborn Oct. 30, 1945 2,491,048 Jenkins Dec. 13, 1949 2,675,657Taggert et a1. Apr. 20, 1954

